Chapter 7 Climate and Biodiversity Blowing in the Wind: A Story of Connections Wind connects most life on earth. Keeps tropics from being unbearably hot. Keeps tropics from being unbearably hot. Prevents rest of world from freezing. Prevents rest of world from freezing. Figure 5-1 Weather vs. Climate Weather- changes in properties of the troposphere in a given place and time. i.e.: temperature, pressure, humidity, wind, air, and cloud cover. Troposphere- 11 miles above sea level. Most of the air surrounding earth is in this thin layer. Mostly nitrogen 78% and oxygen 21% (by volume) Climate- average weather of an area overtime (30 years) Climate and Air Circulation Circulation of air over Earths atmosphere is the main reason for variation in climates. Determines average temperature and precipitation Figure 5-3 Air Circulation is Caused by: 1. Changes in solar energy reaching earth a. Slight changes in earths slant a. Slight changes in earths slant b. Slight changes in shape of orbit b. Slight changes in shape of orbit c. Slight changes in solar output overtime c. Slight changes in solar output overtime Air Circulation is Caused by: 2. Differences in solar energy reaching various parts of earth or uneven heating of earths surface a. Air is heated much more at equator than at poles (direct sun, not angle) Air Circulation is Caused by: 3. Tilt of earth- opposite seasons for N & S Hemisphere (page 102) Air Circulation is Caused by: 4. Rotation of earth a. Prevents air currents from moving due N or S, p. 102 b. Determines prevailing winds, redistributes air, moisture, and dust over Earths surface c. Coriolis Effect page 102 figure 5.4 Air Circulation is Caused by: 5. Properties of air and water a. Warm= rise, expand p. 103 Figure 5.5 b. Cool=fall, contractc. Results in 6 huge convection cells p. 103 Figure 5.6 Convection Currents Global air circulation is affected by the properties of air water, and land. Figure 5-5 Convection Cells Heat and moisture are distributed over the earths surface by vertical currents, which form six giant convection cells at different latitudes. Figure 5-6 Climate All of these factors determine the climate Climate determines flora (plant life) Climate determines flora (plant life) Flora determines fauna of an area (animal life) Flora determines fauna of an area (animal life) Climate and Ocean Currents 1. Large circular water movements are caused by trade winds. Water is pushed westward until it hits land and turns; redistributes heat Ex: Warm currents make Alaska and Japan warmer than predicted. Page S39 (back index) Climate and Ocean Currents 2. Nutrients from bottom are pushed upward creating an area that can support large numbers of microscopic plants and animals (plankton) Climate and Ocean Currents 3. Areas of increased salinity or cooling water are denser and sink. Forms deep underwater currents known as upwellings -Nutrients redistributed and temps mixed El Nino - Every few years the E to W pattern is broken by a climate shift. Usually starts in December (hence the name) Usually starts in December (hence the name) Can last 3 months to 1+ year Can last 3 months to 1+ year Disrupts nutrient cycling off coast of S. America so populations of plankton, fish and birds are effected. Disrupts nutrient cycling off coast of S. America so populations of plankton, fish and birds are effected. Ocean Currents: Distributing Heat and Nutrients Ocean currents influence climate by distributing heat from place to place and mixing and distributing nutrients. Figure 5-7 Climate and Chemical Composition of the Atmosphere Certain chemicals determine earths avg. temp. a.CO2, H20 vapor, 03, CH4, NO, CFCs (carbon dioxide, water vapor, ozone, methane, nitrous oxides, chlorofluorocarbons) a.CO2, H20 vapor, 03, CH4, NO, CFCs (carbon dioxide, water vapor, ozone, methane, nitrous oxides, chlorofluorocarbons) b. Mars has none of these=frozen c. Venus has high levels= burning hot d. Earth has right amount for life, as we know it. Climate and Chemical Composition of the Atmosphere Most of the gases act like the glass of a greenhouse (allowing in sunlight and holding the heat near the Earths surface) CFCs tie up oxygen atoms and prevent 03 formation Climate and Chemical Composition of the Atmosphere 03 forms when 02 react with u.v. rays, unstable gas 03 filters u.v. rays so we dont get too many of these harmful rays A decrease in 03 or increase on other gases listed may lead to the Greenhouse Effect (theory that the Earth is heating more quickly than predicted due to human activity) Ocean Currents: Distributing Heat and Nutrients Global warming: Considerable scientific evidence and climate models indicate that large inputs of greenhouse gases from anthropogenic (manmade) activities into the troposphere can enhance the natural greenhouse effect and change the earths climate in your lifetime. Considerable scientific evidence and climate models indicate that large inputs of greenhouse gases from anthropogenic (manmade) activities into the troposphere can enhance the natural greenhouse effect and change the earths climate in your lifetime. Climate and Topography (shape of the land) 1. Mountains block storms Cooler, wetter, windier than lower elevations (west side) Cooler, wetter, windier than lower elevations (west side) Winds blow from North West. East side is dry. Rain Shadow Effect p. 105 Figure 5.8 Ex. Sierra Nevada Mtn. Range Ex. Sierra Nevada Mtn. Range West side lush, east side is Mojave Desert West side lush, east side is Mojave Desert BIOMES: CLIMATE AND LIFE ON LAND Different climates lead to different communities of organisms, especially vegetation. Biomes large terrestrial regions characterized by similar climate, soil, plants, and animals. Biomes large terrestrial regions characterized by similar climate, soil, plants, and animals. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors. Biomes p-106 Figure 5.9 Precipitation, latitude, altitude determine type of biome. Know basic characteristics of major biomes. 1. Desert=